Method and apparatus for converting hydrocarbons



L. J. WALSH Aug. 20, 1929.

METHOD AND APPARATUS FOR CONVERTING HYDROCARBONS Filed NOV. 28, 1923 I W l w W Z Louis J Way/5h.

Patented Aug, 20, 1929.

UNITED .STATES' 1,125,434 PATENT OFFICE.

m r LOUIS J. WALSH, OF BELMONT, MASSACHUSETTS, ASSIGNOR TO STANDARD OIL DE- VELOPMENT COMPANY, A CORPORATION OF DELAWARE.

METHOD AND APPARATUS FOR CONVERTING HYDBOCARBONS.

Application filed November 28, 1923. Serial No. 677,864.

This inventidn relates to the art of converting hydrocarbons into lower boiling products, and will be fully understood from the following description, taken in connection with the accompanying drawing which represents in side elevation, with parts in section, a form of embodiment of the invention.

Referring to the drawing, the numeral 2 designates a heating conduit or coil of any suitable character, for instance, parallel tubes joined serially by end connections and mounted over a furnace and supplied by oil through the feed ,pipe 1 and having a discharge pipe3 leading upwardly to a point of discharge in the intermediate port-ion of a drum 4. The drum is guarded against material heat loss, as by a covering of insulation 5 or a flue-gas jacket and has manheads above and below to allow of ready cleaning. Leading from near the top of the drum is an outlet pipe 6 which may be equipped with a pressure-release valve 7 and which discharges into a vapor-separator 8. From a point near the bottom of the drum 4 a pipe 9 leads up andconnects into the pipe 6 at a point only a little below its top. The vapor-separator 8 is provided with a vapor otf-take 10 leading to any desired system of for removal of residual liquid. As is well known in the art, condensation may be ef fected in a system including a fractionatingtower and condensing means, reflux condensate being mixed with fresh charging oil and forwarded to the cracking oil.

In operation, oil being fed through the heating conduit 2 is heated up to cracking temperature or is cracked to. the extent desired and is passed on into the drum 4 where it is maintained at cracking temperature while slowly proceeding to the outletpipe 6. Pressure is maintained upon the system by setting the release-valve 7 as desired, ordinarily for example at least 250 lbs. per square inch, and products passing through the pipe 6 past the valve 7 escape into the vapor-separator 8 where vapors disengaged are taken off to the condensers and residual liquid is withdrawn through pipe 11. During the operation carbon and tarry matters are formed and settle down in the drum 4. Such material tends to accumulate to a detrimental extent ordinarily, but by virtue of the pipe 9 in the present invention it is condensers (not shown), and a drain-line 11 continuously passed out from the bottom of the drum into the pipe 6 and discharges in the vapor-separator where it is stri. ped of contained vaporizable fractions be ore bemg withdrawn through pipe'll. The relation of the pipes 9 and 6 can be so adapted that the tarry sedimentary matter is gent.- ly taken off by the slight head of ressure represented in the. difference of level etween the outlet points of the respective pipes, and in this manner violent currents in the drum tending to prematurel sweep out portions of oil are avoided. l or example with a drum 30 feet high operating at 250 lbs. pressure per square inch the distance'between connection 9 and outlet opening 6 may be not over 2 feet and advantageously about 21 inches. Vapors and light liquid products flow through pipe 6'.

While my invention is best illustrated in the case of a vertical cracking drum, it. will be understood that the invention 'is applicable in proportionate degree with other forms of oil drums, in which an outlet open-' ing at or near the top can be arranged, and a draw-off pipe also, leading from a point at or near the bottom of the drum but discharging by an eflective difference of level (and corresponding difference of pressure) only slightly lower than the top outlet opening. 7

What I claim is:

1. The combination of a heating conduit,

-a vertical drum about thirty feet high insulated against material heat loss and connected to receive the discharge from the heating conduit in its intermediate portion, a vapor separator, an outlet pipe leading from near the top of the drum and discharging into the vapor separator, a pressure-release valve in said outlet pipe, and a tar draw-oft pipe leading from a point near the bottom of said drum to connect into said outlet pipe at a point not exceeding two feet below the top outlet opening.

2. Oil cracking apparatus comprising a coil, means for heating the same, a thermally insulated drum connected to the coil, an outlet ipe leading from near the top of the drum an serving as the sole means for withdrawing lighter products therefrom, a vapor separator into which the outlet pipe discharges, a pressure release valve in the outlet pipe, and a tar draw-ofi pipe leading from near the bottom of the drum to connect into the outlet pipe at a point not far below the top opening of the outlet pipe and adapted towxthdraw heavy tarry products accumulating 1n the bottom of the drum.

I reducing valve thereon. I

5. Oil cracking apparatus comprising a coil, means for heating the same, a thermally insulated drum connected to the coil, a single discharge line comprising two branch pipes, one of relatively small diameter leading from near the top of the drum, the second of larger diameter leading from the bottom thereof, said branch pipes joining to form a united line, and a pressure reducing means in theunited line.

I 6. In. a method of withdrawing converted hydrocarbon material from a reaction drum, the improvement which comprlses settling tarry material during the conversion, withdrawing such material from near the bottom of the drum, withdrawing vapors from near the top of the drum, combining the withdrawn tarry material and vapors into a single stream, and reducing pressure on the withdrawn stream.

I 7. In a method of withdrawing converted hydrocarbon material from a reaction zone under pressure, the improvement which comprises-settling tarry material during the conversion, flowing lighter products downwardly in a confined stream,- from near the top of the reaction zone, tappingofi said tarry material in a'ai'oii'fined upflowing stream communicating in the upper part of said zone with the stream of lighter products, said upflowing stream of tarry material being shorter than said downfiowing stream of admixed tar and lighter products. whereby a hydrostatic head causing flow of tarry material is provided, reducing the pressure on the combined streams of tarry materialand lighter products, and withdrawing and condensing vapor produced thereby.

8. An oil cracking method, comprising heating a stream of the oil to a cracking temperature, passing the hot stream into a thermally insulated reaction zone under pressure in which zone the oil tends to form a lower layer of tar and an upper layer of lighter products, continuously withdrawing said lighter products, continuously withdrawing tar, mixing the lighter products and tar, reducing the pressure on the mixture whereby the more volatile components of the lighter products and tar are vaporized, and withdrawing and condensing the vapors so formed.

9. An oil cracking method, comprising heating a stream of the oilto a cracking temperature under pressure; passing the hot stream-into a thermally insulated reaction zone under pressure and in which the oil tends to form a lower layer of tar and an upper layer of lighter products, continuously withdrawing lighter products from near the top of the reaction zone, continuously withdrawing tar from near the bottom of said zone, combining said lighter products and tar into a single-stream, withdrawing-said stream and passing the same at reduced pressure into a vaporizing zone and withdrawing and condensing vapors formed therein;

LOUIS J. WALSH. 

